A panel of a color cathode ray tube is provided with not only a screen, but also with a shadow mask for filtering the electron beams advancing toward the screen and a frame for supporting the shadow mask. The frame for supporting the shadow mask is disposed alongside the inner space of the panel by means of a stud pin imbedded on the inner face of the skirt of the panel with some portion thereof protruding, while the stud pin is used for holding a flat plate spring which is weld-fixed at several spots on the side face of the frame.
The above mentioned flat spring serves a role of attaching the shadow mask frame assembly to the panel, and also serves the role of electrically connecting the shadow mask frame assembly to the screen provided on the inner face of the panel. This electrical connection is needed for bypassing the useless electrons remaining on the screen through the shadow mask frame assembly to the ground. The above mentioned useless electrons are indicative of those electrons which can not contribute to realization of the images upon landing upon the screen, and those electrons which remain on the screen after having contributed to realization of the images. Therefore, the structure of the electrical connection between the shadow mask frame assembly and the screen plays an important role.
In the conventional structure of the above mentioned electrical connection, however, there has been a definite factor for product defects which can be attributable to the defective electrical connections, and one of the electrical connections liable to cause the product defects is the connection between the stud pin and the screen.
Generally, as shown in FIGS. 1 and 2, the electrical connection between the stud pin and the screen is constituted such that an aluminum coating layer 3 as one element of the screen is extended to a part of the body of the stud pin 2.
During the process for depositing aluminum coating layer 3, the evaporated aluminum atoms can not reach sufficiently to the portion shielded by the stud pin 2, i.e., the portion A on the drawing, thereby making it impossible to expect a perfect electrical connection between the stud pin and the screen. Such a phenomenon frequently occurs actually through the manufacturing process, and to overcome this problem, graphite which is a conductive material is supplementally spread. The use of graphite, however, can also bring problems, such that the graphite layer itself is formed in an imperfect manner so as for the intended target not to be attained, or that, during the spreading of graphite, the graphite fluid can splash on the screen, i.e., the aluminum coating layer so, as for the screen to be polluted.